1. From the Department of Clinical Epidemiology (R.E.J.R., W.M.L., F.R.R., S.C.C., S.l.C.), Einthoven Laboratory for Experimental Vascular Medicine (W.M.L., F.R.R., S.C.C.), Thrombosis and Hemostasis Research Center (F.R.R.), and Department of Medical Statistics and Bioinformatics (S.l.C.), Leiden University Medical Center, Leiden, The Netherlands.